Grading machine

Abstract

A grading machine (10) is disclosed. The grading machine (10) includes a main frame (14), a center frame (16), and a rear frame (18). A grading blade (20) is connected to the main frame (14) for pivotable motion about a vertical axis. A pair of spaced wheels (22) is carried by the rear frame (18). The tilt of the blade (20) can be adjusted by rotating the center frame (16) and the main frame (14) connected thereto about a horizontal axis extending in the direction of travel of the machine (10). The height of the blade (20) can be adjusted by adjusting the angular relationship between the center frame (16) and the main frame (14) about a second horizontal axis of a coupling rod (96).

I claim: 
     
       1. A grading machine comprising a main blade support frame, a center connecting frame and a rear wheel support frame, said main frame extending longitudinally between a forward and a rearward end and having means for coupling the forward end to a vehicle, said center connecting frame being pivotably coupled to the rearward end of said main frame about a generally horizontal axis extending in a first direction transverse to the longitudinal direction of said main frame, and said center frame being pivotably coupled to said rear frame for motion about a second generally horizontal axis extending in said longitudinal direction whereby said rear wheel support frame is coupled to said main blade support frame for pivotal motion about two generally horizontal axes perpendicular to one another by way of said separate center connecting frame, a grading blade, means for connecting said grading blade to said main frame for pivoting motion about a vertical axis, ground contacting wheels carried by said rear wheel support frame, first powered means coupled between said main and center frames for pivoting said main frame about said first horizontal axis to adjust the vertical height of said grading blade with respect to the ground and said rear frame, and second powered means coupled between said rear and center frames for pivoting said main frame about said second horizontal axis to adjust the tilt of said grading blade. 
     
     
       2. A grading machine in accordance with claim 1 wherein said center frame includes a rearwardly extending tubular member and said rear frame includes a hollow cylindrical member within which said tubular member is rotatably received. 
     
     
       3. A grading machine in accordance with claim 2 wherein said second powered means includes a hydraulic cylinder device having a first end pivotably connected to said rear frame and a second end pivotably connected to said center frame, and means for controlling the application of pressurized hydraulic fluid to said cylinder device to control the rotary position of said tubular member with respect to said cylindrical member whereby the tilt of said grading blade is controlled. 
     
     
       4. A grading machine in accordance with claim 1, 2 or 3 wherein said first powered means includes includes a second hydraulic cylinder device having a first end pivotably connected to said center frame and a second end pivotably connected to said main frame, and means for controlling the application of pressurized hydraulic fluid to said second hydraulic cylinder device to control the pivotal relationship between said main frame and said center frame whereby the vertical position of said grading blade is controlled. 
     
     
       5. A grading machine in accordance with claim 1, 2 or 3 wherein said means for connecting said grading blade to said main frame includes a control arm connected to said blade and extending in a generally longitudinal direction, said control arm being pivotably connected to said main frame about a generally vertical axis, and including a third hydraulic cylinder device having a first end pivotably connected to said main frame and a second end pivotably connected to said control arm, and means for controlling the application of pressurized hydraulic fluid to said third hydraulic cylinder device whereby the angular disposition of said grading blade is controlled. 
     
     
       6. A grading machine in accordance with claim 1 including means for turning said wheels about a generally vertical axis to steer said machine. 
     
     
       7. A grading machine comprising a main frame, a center frame, a rear frame, a grading blade connected to said main frame for pivoting motion about a generally vertical axis through a blade frame, said blade frame including a control arm having a first end pivotably connected to said main frame about said vertical axis and a portion spaced from said first end and slidably supported by a transverse across brace of said main frame, a first hydraulic cylinder device having a first end connected to said main frame and a second end pivotably connected to said arm for pivoting said arm about said vertical axis to adjust the angular disposition of said grading blade, a pair of spaced wheels rotatably carried by said main frame, means for steering said wheels, said center frame including a forward portion and a tubular member extending rearwardly therefrom, a pivot rod extending through apertures in said main frame and a hole in said forward portion of said center frame to pivotably connect said center frame to said main frame about a first generally horizontal axis, a second hydraulic cylinder device having a first end pivotably connected to said center frame and a second end pivotably connected to said main frame for adjusting the angular relationship between said center and main frames to adjust the height of said grading blade, said tubular member being rotatably coupled to said rear frame for rotation about a second generally horizonatal axis perpendicular to said first horizontal axis, a third hydraulic cylinder device having a first end pivotably connected to said rear frame and a second end pivotably connected to said center frame for rotating said tubular member and said center frame about said second axis to adjust the tilt of said grading blade, and means for controlling the supply of pressurized hydraulic fluid to said first, second and third hydraulic cylinder devices. 
     
     
       8. A grading machine comprising a main frame, a grading blade, means for connecting said grading blade to said main frame for pivoting motion about a vertical axis, means for moving said grading blade about said vertical axis, a rear frame, means for contacting the ground carried by said rear frame, means for connecting said rear frame to said main frame about two horizontal axes perpendicular to one another, said connecting means including a center frame, said center frame having a rearwardly extending tubular member, said rear frame including a hollow cylindrical member within which said tubular member is received for rotation about one of said horizontal axes, and a pivot rod extending through aligned holes in said main frame and a forward portion of said center frame in the direction of a second of said horizontal axes, means for vertically moving said main frame with respect of rear frame to adjust the height of said grading blade, and means independent of said vertical moving means for pivoting said main frame with respect to said rear frame about an axis generally in the direction of motion of the machine to adjust the tilt of said grading blade. 
     
     
       9. A grading machine in accordance with claim 8 wherein said blade connecting means includes a blade frame attached to said grading blade, said blade frame including a support member attached to and extending upward from said grading blade and a control arm extending from said support member, said control arm having a first end pivotable connected to said main frame and a distal portion slidably carried on a transverse member of said main frame. 
     
     
       10. A grading machine in accordance with claim 9 wherein said means for moving said grading blade about its vertical axis includes a hydraulic cylinder device having a first end pivotably connected to said main frame and a second end pivotably connected to said control arm. 
     
     
       11. A grading machine comprising a main frame, a grading blade, a blade frame for connecting said grading blade to said main frame for pivoting motion about a vertical axis, said blade frame including a support member attached to and extending upward from said grading blade and a control arm extending from said support member, said control arm having a first end pivotable connected to said main frame and a distal portion slidably carried on a transverse member of said main frame, means for moving said grading blade about said vertical axis including a hydraulic cylinder device having a first end pivotably connected to said main frame and a second end pivotably connected to said control arm, a rear frame, means for contacting the ground carried by said rear frame, means for connecting said rear frame to said main frame, means for vertically moving said main frame with respect of rear frame to adjust the height of said grading blade, and means independent of vertical moving means for pivoting said main frame with respect to said rear frame about an axis generally in the direction of motion of the machine to adjust the tilt of said grading blade. 
     
     
       12. A grading machine in accordance with claim 11 wherein said connecting means couples said rear frame to said main frame about two horizontal axes perpendicular to one another. 
     
     
       13. A grading machine in accordance with claim 12 wherein said connecting means includes a center frame, said center frame pivotably connected to said main frame about one of said horizontal axes and pivotally connected to said rear frame about the other of said horizontal axes. 
     
     
       14. A grading machine in accordance with claim 12 wherein said connecting means includes a center frame, said center frame having a rearwardly extending tubular member, said rear frame includes a hollow cylindrical member within which said tubular member is received for rotation about one of said horizontal axes, and a pivot rod extending through aligned holes in said main frame and a forward portion of said center frame in the direction of a second of said horizontal axes. 
     
     
       15. A grading machine in accordance with claim 14 wherein said means for pivoting said main frame with respect to said center frame to adjust the tilt of said grading blade includes a hydraulic cylinder device having a first end pivotably connected to said rear frame and a second end pivotably connected to said center frame for rotating said tubular member with respect to said cylindrical member. 
     
     
       16. A grading machine in accordance with claim 14 or 15 wherein said means for vertically moving said main frame includes a second hydraulic cylinder device having a first end pivotably connected to said center frame and a second end pivotably connected to said main frame for varying the angular relationship between said main and center frames about said pivot rod. 
     
     
       17. A grading machine in accordance with claim 15 wherein a lever arm extends outward from said tubular member and the pivotable connection at said second end of said hydraulic cylinder device is located on said lever arm a distance from the outer surface of said tubular member. 
     
     
       18. A grading machine in accordance with claim 8 or 11 wherein said ground contacting means includes a pair of wheels rotatably carried on an axle connected to said rear frame, said wheels being pivotable about vertical axes, and steering means for pivoting said wheels about their vertical axes. 
     
     
       19. A grading machine in accordance with claim 18 wherein said steering means includes a hydraulic cylinder device connected to a control rod for pivoting one of said wheels and a tie rod connected to a control rod for pivoting one of said wheels, and a tie rod connected to a control rod of the other wheel to pivot said wheels in unison.